By the way the error I get when connecting to a sub account is:
Connect socket #780 to xx.x.x66.223, port 31231...
150 Accepted data connection
226-File successfully transferred
226 0.084 seconds (measured here), 104.08 Kbytes per second
MDTM 20041105180922 sslstarter.gif
550 Can't check for file existence
PASV
Transfer time: 00:00:01
227 Entering Passive Mode (xx,x,x66,223,90,220)
LIST -al
Connect socket #796 to xx.x.x66.223, port 23260...
150 Accepted data connection
226-ASCII
226-Options: -a -l
226 3 matches total
Resolving mydomain.com...
Connect socket #836 to xx.x.x74.2, port 21...
220 (vsFTPd 1.2.1)
USER
myusername@mydomain.com
331 Please specify the password.
PASS **********
530 Login incorrect.